chore: add copyright year to footer

Author: molty3000

docs/index.html

@@ -408,7 +408,7 @@ <h2>One command. Zero dependencies.</h2>
 <!-- Footer -->
 <footer class="footer">
   <div class="container">
-    <p><a href="https://github.com/BackendStack21/go-mcp" target="_blank" rel="noopener">BackendStack21/go-mcp</a> — MIT License</p>
+    <p>© 2026 <a href="https://github.com/BackendStack21/go-mcp" target="_blank" rel="noopener">BackendStack21/go-mcp</a> — MIT License</p>
   </div>
 </footer>